Large Galaxy Caught in the Making
This image shows the radio galaxy MRC 1138-262, nicknamed the “Spiderweb Galaxy”, sitting at the center of an emergent galaxy cluster, surrounded by hundreds of other galaxies from the cluster.
Credit: NASA, ESA, George Miley and Roderik Overzier (Leiden Observatory, the Netherlands)

Astronomers have long suspected that most large galaxies form at least in part by acquiring smaller galaxies in dramatic cosmic mergers.

New images from the Hubble Space Telescope support that view.

Hubble photographed the Spiderweb Galaxy [image], officially MRC 1138-262. It is 10.6 billion light-years away. The light we see from it emanated when the universe was only a couple billion years old.

The Spiderweb Galaxy sits amid an emerging galaxy cluster [image], and dozens of young, small, star-forming galaxies are seen merging into the Spiderweb.

"The new Hubble image is the best demonstration so far that large massive galaxies are built up by merging smaller ones," said study leader George Miley from Leiden Observatory in The Netherlands.

Galaxies are being drawn by gravity into the Spiderweb from a sphere more than 100,000 light-years across. The galaxies are racing in at hundreds of miles per hour.

The Spiderweb Galaxy is located in the southern constellation Hydra (the water snake) and is one of the most massive galaxies known.

This finding, announced today, are detailed in the October 10 issue of Astrophysical Journal Letters.